7.2. Engineering use of the garden

Garden engineering is “a new symbiosis of nature and technology. The concept of designing modern buildings is based on the idea that the quality of our environment has a direct impact on our quality of life. This social dimension is the recognition that architecture and construction evolve based on the needs of people, spiritual and material.

American scientist David Orr formulated the principles according to which an energy efficient building should be designed and built:

• construction and operation of the building should contribute to the development of technologies related to the use of the environment;

• the construction of the building should contribute to the creation of a landscape that enhances the biological diversity of plant species;

• the building must not “produce” any wastewater, that is, the building must not only consume, but also drain water suitable for drinking;

• the building must produce more electrical energy than it uses;

• no carcinogenic, mutagenic, or endocrine disease-causing materials should be used in the building;

• energy and materials should be used as efficiently as possible;

• the building must use materials and equipment produced without harming the environment;

• The construction and operation of the building should contribute to the development of environmental competence and attentiveness to the environment.

Closed-cycle buildings are more advanced than energy-efficient systems that use non-traditional renewable energy sources and do not require external water inflows.

Garden as one of the elements of the engineering system

One of the most actively developing areas in modern architecture is the use of gardens in a building as one of the elements of the engineering system. Here the gardens bear not only aesthetic, but also other functions: they are heat insulation, participate in the process of wastewater treatment, are included in the ventilation system of the premises.

Designed by Norman Foster (Sir Norman Foster) and his studio Foster and Partners and completed in 1997, the Commerzbank Tower (the official name Commerzbank will be used later) rises in the heart of the city’s financial district of Frankfurt am Main, Germany. The Commerzbank building is ranked 24th in the world in height and is the highest in Europe.

It uses mainly natural light and natural ventilation, there is an atrium that runs from ground level to the top floor, with every office or part of the building offering views of the city. Spiral throughout the building are four-storey winter gardens - they improve the microclimate and create a completely different ecological environment.

Norman Foster considered plants to be more than just decoration. These magnificent gardens are a fundamental element of his concept. Nine conservatories spirally border the entire building; three are located on the east side, three are on the south and three more are on the west. In the botanical aspect, the following plants are selected;

• on the east side - Asian vegetation (astilbe, bamboo, Asian maple, magnolia, azalea, hibiscus);

• on the south side - Mediterranean vegetation (thyme, olive tree, oleander, lavender, pomegranate, cypress, citrus);

• on the west side - North American vegetation (maple, mammoth tree - sequoia, dendron, rhododendron, aster).

The four-storey open spaces of the gardens provide the internal office space with ample daylight. In addition, these gardens can be used by staff for socializing and relaxing - they create a sense of space, and are also part of a complex natural ventilation system.

The latest scientific and technical developments are used in these gardens to find lost connections with nature. That is, in cities where the gap with nature is most noticeable, the possibility of using gardens as part of the engineering system returns comfort to the environment, and turns houses into oases of greenery and comfort.

Garden as part of closed-loop buildings

The garden is a necessary part of closed-cycle buildings being developed today. The development of such buildings, which do not require external sources of energy and water, has long been occupied by engineers and architects. Thus, in January 2000, the Adam Joseph Lewis Center for Environmental Studies was opened in Oberlin (Ohio, USA). Perhaps the most important idea in the architecture and construction of the 21st century is nature as a non-passive background of human activity: a new natural environment can be created with higher comfortable indicators for urban planning and at the same time an energy source for building air-conditioning systems.

Therefore, one of the main innovative environmental features of the Center’s project was a garden with the installation of the Living Machine wastewater treatment system, improved by John Todd. Developments of such installations were made earlier in Europe, in particular in Germany. The Living Machine is a local wastewater treatment system that combines conventional wastewater treatment technologies and natural ecosystem cleaning processes. “The Living Machine installation performs three types of wastewater treatment: the removal of organic contaminants, disinfection and the removal or reduction of water concentrations of substances such as nitrogen and phosphorus, which can cause environmental damage. Organic contaminants are decomposed by sunlight and controlled organic processes that use living organisms — bacteria, plants, zooplankton, and invertebrates. Depending on the climate, the Living Machine installation can be placed in a protected greenhouse, under light shelter or in an open area. Unlike traditional cleaning systems, the unit does not emit any unpleasant odors, which allows it to be placed in close proximity to the premises.

The Adam Joseph Lewis Center's Living Machine wastewater treatment plant uses a system that includes germs, plants, snails and insects. Traditional methods of chemical wastewater treatment do not apply. The capacity of this plant is about 10 thousand liters of wastewater daily. Wastewater treated by the plant is returned and reused as non-potable water, for example, in toilets.

But there is, in addition to the listed advantages, also an artistic effect. The main part of the installation is located in the greenhouse, adjacent to the atrium and an audience of 100 seats. Wastewater is passed through a number of biological communities inhabited by microorganisms that help reduce the level of organic pollutants, as well as nitrogen and phosphorus. Water undergoes treatment in several special septic tanks.

After the sump, water enters an artificial marsh located in the greenhouse. A 91 cm thick gravel pad is placed on the greenhouse floor. Stones and roots of plants such as sedge, iris and reed provide habitat for denitrifying bacteria. Gravel and organic matter are also removed and a portion of the phosphorus contained in the water is precipitated. Water trickles from the east side of the greenhouse to the west, where it is collected and sent to an outdoor collection tank.

Purified water from the outdoor collection tank as needed enters the UV disinfection unit. Under the influence of ultraviolet rays, bacteria are destroyed. Purified and disinfected water is pumped under pressure into a sealed tank, from where it is used if necessary.

On a plot of 28.33 hectares, owned by the Center, there are also gardens for growing agricultural products, places for recreation and walks, bogs and a reservoir are located, allowing rainwater to be collected for use in irrigation. It is planned to continue to use part of this water for the water supply of the building.

Placing plants around the buildings of the Center is not accidental. As the studies of architects have shown, in people of different eras and nationalities, the concept of Paradise is consistently associated with the image of a garden. Therefore, in order to raise the quality of housing, it is necessary to place it in the garden, and in the northern climate it is desirable to additionally arrange a winter garden in the house.

The plants in the house can improve the hygienic conditions, the aesthetic qualities of the home, they can bear fruit and produce crops, and far from being symbolic. Ecological dwelling house should provide its inhabitants with great opportunities for plant growing both in the house and in the adjacent plot. It can house an attached greenhouse and a winter garden, and special biocultural plants are available for year-round cultivation of vegetables, edible algae, etc.

Thus, the principle of using the garden as the main component of the new generation of buildings shows that gardens now play in architecture not only an aesthetic, but also a serious practical role. This, ultimately, improves the ecology of the building, creates a comfortable environment for the life and work of people, improves the quality of life itself [1].